Refactor timer class

CHANGELOG.md

@@ -3,6 +3,7 @@
 ## [next]
  - Improve IsometricTileMap and Spritesheet classes
  - Export full vector_math library from extension
+ - Refactor timer class
 
 ## 1.0.0-rc1
  - Move all box2d related code and examples to the flame_box2d repo

doc/examples/particles/lib/main.dart

@@ -19,7 +19,7 @@ import 'package:flame/particles/animation_particle.dart';
 import 'package:flame/particles/component_particle.dart';
 import 'package:flame/flame.dart';
 import 'package:flame/game.dart';
-import 'package:flame/time.dart' as flame_time;
+import 'package:flame/timer.dart' as flame_time;
 import 'package:flame/particle.dart';
 import 'package:flame/extensions/vector2.dart';
 import 'package:flame/sprite.dart';

doc/examples/timer/lib/main.dart

@@ -1,6 +1,6 @@
 import 'package:flutter/material.dart';
 import 'package:flame/game.dart';
-import 'package:flame/time.dart';
+import 'package:flame/timer.dart';
 import 'package:flame/text_config.dart';
 import 'package:flame/gestures.dart';
 import 'package:flame/extensions/vector2.dart';
@@ -68,9 +68,11 @@ class MyGame extends Game with TapDetector {
 
   MyGame() {
     countdown = Timer(2);
-    interval = Timer(1, repeat: true, callback: () {
+    interval = Timer(
-      elapsedSecs += 1;
+      1,
-    });
+      callback: () => elapsedSecs += 1,
+      repeat: true,
+    );
     interval.start();
   }
 

doc/util.md

@@ -59,7 +59,7 @@ import 'dart:ui';
 
 import 'package:flame/game.dart';
 import 'package:flame/text_config.dart';
-import 'package:flame/time.dart';
+import 'package:flame/timer.dart';
 import 'package:flame/vector2.dart';
 
 class MyGame extends Game {
@@ -73,15 +73,18 @@ class MyGame extends Game {
   @override
   void update(double dt) {
     countdown.update(dt);
-    if (countdown.isFinished()) {
+    if (countdown.finished) {
-      // do something ...
+      // Prefer the timer callback, but this is better in some cases
     }
   }
 
   @override
   void render(Canvas canvas) {
-    textConfig.render(canvas, "Countdown: ${countdown.current.toString()}",
+    textConfig.render(
-        Vector2(10, 100));
+      canvas,
+      "Countdown: ${countdown.current.toString()}",
+      Vector2(10, 100),
+    );
   }
 }
 
@@ -94,7 +97,7 @@ import 'dart:ui';
 
 import 'package:flame/game.dart';
 import 'package:flame/text_config.dart';
-import 'package:flame/time.dart';
+import 'package:flame/timer.dart';
 import 'package:flame/vector2.dart';
 
 class MyGame extends Game {
@@ -104,9 +107,11 @@ class MyGame extends Game {
   int elapsedSecs = 0;
 
   MyGame() {
-    interval = Timer(1, repeat: true, callback: () {
+    interval = Timer(
-      elapsedSecs += 1;
+      1,
-    });
+      callback: () => elapsedSecs += 1,
+      repeat: true,
+    );
     interval.start();
   }
 
@@ -128,7 +133,7 @@ Timer instances can also be used inside a `BaseGame` game by using the `TimerCom
 __Timer Component__
 
 ```dart
-import 'package:flame/time.dart';
+import 'package:flame/timer.dart';
 import 'package:flame/components/timer_component.dart';
 import 'package:flame/game.dart';
 
@@ -136,9 +141,11 @@ class MyBaseGame extends BaseGame {
   MyBaseGame() {
     add(
       TimerComponent(
-        Timer(10, repeat: true, callback: () {
+        Timer(
-          print("10 seconds elapsed");
+          10,
-        })
+          callback: () => print("10 seconds elapsed"),
+          repeat: true,
+        )
         ..start()
       )
     );

lib/components/timer_component.dart

@@ -1,6 +1,6 @@
 import 'dart:ui';
 
-import '../time.dart';
+import '../timer.dart';
 import 'component.dart';
 
 /// Simple component which wraps a [Timer] instance allowing it to be easily used inside a [BaseGame] game.
@@ -19,5 +19,5 @@ class TimerComponent extends Component {
   void render(Canvas canvas) {}
 
   @override
-  bool destroy() => timer.isFinished();
+  bool destroy() => timer.finished;
 }

lib/particle.dart

@@ -12,7 +12,7 @@ import 'particles/moving_particle.dart';
 import 'particles/rotating_particle.dart';
 import 'particles/scaled_particle.dart';
 import 'particles/translated_particle.dart';
-import 'time.dart';
+import 'timer.dart';
 
 /// A function which returns [Particle] when called
 typedef ParticleGenerator = Particle Function(int);
@@ -84,10 +84,6 @@ abstract class Particle {
   /// Marks [Particle] for destroy when it is over.
   void update(double dt) {
     _timer.update(dt);
-
-    if (_timer.progress >= 1) {
-      _shouldBeDestroyed = true;
-    }
   }
 
   /// A control method allowing a parent of this [Particle]
@@ -98,7 +94,8 @@ abstract class Particle {
   void setLifespan(double lifespan) {
     _lifespan = lifespan;
     _timer?.stop();
-    _timer = Timer(lifespan);
+    final void Function() destroyCallback = () => _shouldBeDestroyed = true;
+    _timer = Timer(lifespan, callback: destroyCallback);
     _timer.start();
   }
 

lib/time.dart

@@ -1,53 +0,0 @@
-/// Simple utility class that helps handling time counting and implementing interval like events.
-///
-class Timer {
-  final double _limit;
-  void Function() _callback;
-  bool _repeat;
-  double _current = 0;
-  bool _running = false;
-
-  Timer(this._limit, {bool repeat = false, void Function() callback}) {
-    _repeat = repeat;
-    _callback = callback;
-  }
-
-  double get current => _current;
-
-  void update(double dt) {
-    if (_running) {
-      _current += dt;
-
-      if (isFinished()) {
-        if (_repeat) {
-          _current -= _limit;
-        } else {
-          _running = false;
-        }
-
-        if (_callback != null) {
-          _callback();
-        }
-      }
-    }
-  }
-
-  bool isFinished() {
-    return _current >= _limit;
-  }
-
-  bool isRunning() => _running;
-
-  void start() {
-    _current = 0;
-    _running = true;
-  }
-
-  void stop() {
-    _current = 0;
-    _running = false;
-  }
-
-  /// A value between 0 and 1 indicating the timer progress
-  double get progress => _current / _limit;
-}

lib/timer.dart

@@ -0,0 +1,54 @@
+import 'dart:math';
+
+/// Simple utility class that helps handling time counting and implementing
+/// interval like events.
+class Timer {
+  final double limit;
+  void Function() callback;
+  bool repeat;
+  double _current = 0;
+  bool _running = false;
+
+  Timer(this.limit, {this.callback, this.repeat = false});
+
+  /// The current amount of ms that has passed on this iteration
+  double get current => _current;
+
+  /// If the timer is finished, timers that repeat never finish
+  bool get finished => _current >= limit && !repeat;
+
+  /// Whether the timer is running or not
+  bool isRunning() => _running;
+
+  /// A value between 0.0 and 1.0 indicating the timer progress
+  double get progress => max(_current / limit, 1.0);
+
+  void update(double dt) {
+    if (_running) {
+      _current += dt;
+      if (_current >= limit) {
+        if (!repeat) {
+          _running = false;
+          return;
+        }
+        // This is used to cover the rare case of _current being more than
+        // two times the value of limit, so that the callback is called the
+        // correct number of times
+        while(_current >= limit)  {
+          _current -= limit;
+          callback?.call();
+        }
+      }
+    }
+  }
+
+  void start() {
+    _current = 0;
+    _running = true;
+  }
+
+  void stop() {
+    _current = 0;
+    _running = false;
+  }
+}